Only allow VLC_OBJECT_MODULE outside of p_libvlc
Only allow VLC_OBJECT_MODULE outside of p_libvlc

Speeds up vlc_list_find(), as we avoid looking up the 200+ plugins for
each vlc_list_find(). Also avoids accidentally stealing objects across
LibVLC instances. IMHO, the object tree should be per-instance, and the
root object should not exist, but that's too big a change yet.

vlc-mirror/vlc,krichter722/vlc,jomanmuk/vlc-2.1,vlc-mirror/vlc,shyamalschandra/vlc,shyamalschandra/vlc,xkfz007/vlc,jomanmuk/vlc-2.2,shyamalschandra/vlc,vlc-mirror/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc-2.1,shyamalschandra/vlc,shyamalschandra/vlc,shyamalschandra/vlc,xkfz007/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.2,krichter722/vlc,vlc-mirror/vlc-2.1,xkfz007/vlc,xkfz007/vlc,jomanmuk/vlc-2.2,krichter722/vlc,xkfz007/vlc,jomanmuk/vlc-2.2,jomanmuk/vlc-2.1,vlc-mirror/vlc,vlc-mirror/vlc,shyamalschandra/vlc,vlc-mirror/vlc-2.1,vlc-mirror/vlc-2.1,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,xkfz007/vlc,krichter722/vlc,krichter722/vlc,jomanmuk/vlc-2.1,jomanmuk/vlc-2.1,xkfz007/vlc,jomanmuk/vlc-2.2,vlc-mirror/vlc,vlc-mirror/vlc,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1,krichter722/vlc,krichter722/vlc,jomanmuk/vlc-2.1,vlc-mirror/vlc-2.1